Predicting high fastball

[totopapa_82_PSN]

How do you guys figure out when a pitcher's gonna throw a high fastball?
Back in the day, if a pitcher shook his head while exchanging signs with the catcher, it usually meant a high fastball.
But in the show 24, I'm not so sure.
Maybe there's a new pattern emerging, like PitchCom's influence or something.
I put fastball slider at maximum for more realistic experience.
How do you catch onto these hints?